HRP20211027A1 - Slope woven textile force and strain sensor - Google Patents

Abstract

The textile diagonally woven force and stretch sensor is made in the form of a diagonally woven textile ribbon (1). It consists of two types of threads with precisely defined characteristics: conventional combed multifilament knitted cotton yarn (2) and knitted electroconductive yarn (3). Conventional combed multifilament knitted cotton yarn (2) consists only of cotton combed yarn (4). The finished electroconductive thread (3) consists of twisted cotton combed yarn (4) and electroconductive threads (5). The above-mentioned knitted yarns are woven using the technique of hand bias weaving without a pronounced special weft system, in such a way that both types of yarn form a diagonal textile fabric in a cloth weave with a characteristic closed edge (6) on which the alternating threads change the direction of the diagonal, and at the same time have the task of preventing the structure from shedding ribbons. Due to the longitudinal action of the force on the textile diagonally woven force and stretch sensor, the ribbon is stretched, which leads to its narrowing and a simultaneous increase in the density of the yarn, as well as the occurrence of compression forces that affect the diagonally woven electrically conductive threads in such a way that the contact resistance is reduced and the overall electrical conductivity of the sensor is increased. in accordance with the magnitude of the stretching force. The slope woven textile force and strain sensor is made in the form of a slope woven textile ribbon (1). It consists of two types of threads with precisely defined characteristics: conventional combed multifilament twisted cotton yarn (2) and twisted electrically conductive yarn (3). Conventional combed multifilament twisted cotton yarn (2) consists only of cotton combed yarn (4). The twisted electrically conductive thread (3) consists of spun cotton combed yarn (4) and electrically conductive threads (5). The above-mentioned twisted yarns are woven using the technique of hand slope weaving without an expressive special weft system in such a way that both types of yarns form a diagonal textile plain fabric in a cloth weave with a characteristic closed edge (6) on which the alternating threads change the direction of the diagonal, and at the same time have the task of preventing the structure from shedding ribbons. Due to the longitudinal action of the force on the slope woven textile force and strain sensor, the ribbon is stretched, which leads to its narrowing and a simultaneous increase in the density of the yarn, as well as the occurrence of compression forces that affect the diagonally woven electrically conductive threads in such a way that the contact resistance is reduced and the overall electrical conductivity of the sensor is increased in accordance with the magnitude of the strain force.

Description

Technical field to which the invention relates

The field of technique to which the invention relates according to the International Classification of Patents MKP is Physics G, Force Measurements G01L, using ohmic resistance changes, i.e. G01L 5/161 and Textiles D, Weaving D03 using a special arrangement of the warp or weft, for example with diagonal warps or wefts, or D03D 13/00.

Technical problem for the solution of which protection is requested

With the development of intelligent clothing, there was a need to incorporate sensors, processors, actuators, batteries, wiring and displays into clothing items. A special problem is the installation of sensors whose task is to monitor the condition in the environment of the garment, inside the garment and the biometric state of the wearer of this type of clothing. It has been shown that the existing types of sensors are most often installed in metal, plastic or glass housings, which are dimensionally significantly larger than the thickness of the fabrics, are prone to breakage and damage, are rigid (inflexible and non-stretchable) and cause an unpleasant sensation when touching the body, irritation, etc. even pain, so they are not suitable for direct incorporation into clothing.

The solution to the mentioned problem is reflected in the invention of a sensor whose structure is mostly textile, which takes on the positive textile characteristics of wearing comfort: softness, flexibility, pliability, stretchability, thermal comfort and contact comfort during direct contact of such a sensor with the skin of the human body. Such a sensor can be directly incorporated into intelligent clothing without impairing the positive characteristics of the clothing. Its execution requires yarn with electrical conductivity properties and a special weaving technique that will give the sensor the necessary elasticity, softness and tensile strength. For the purposes of installing sensors built into intelligent clothing, a force and stretch sensor that can be used as a wearer's respiration sensor by measuring the force and stretch of the chest, and which is sewn directly into the garment in the form of a woven textile elastic band, is most sought after. It is used for registering respiration in sports clothes, but also for medical purposes for the treatment of apnea (stoppage of breathing in adults and infants). Limb movements of athletes and the elderly can also be registered. The stretching forces in such sensors must be small so as not to interfere with breathing and the movement of the body's limbs, and their textile character enables the application of conventional joining techniques used in the technological processes of clothing production.

State of the art

US2007141939A1 describes a sensor having a three-layer construction comprising a first knitted conductive textile plane, a second conductive textile plane and an intermediate separation plane into which the first knitted conductive textile plane penetrates to allow the first conductive textile plane and the second conductive textile plane to achieve electrical contact under mechanical interaction. The middle parting plane defines the structural endpoints from which the first knitted conductive textile plane deforms towards the second conductive textile plane under mechanical interaction. The first knitted conductive textile plane has conductive yarns knitted to form a repeating weave pattern, each of which contains a portion of conductive yarn so that the structure can make electrical contact under the action of force, i.e. forming a textile button or switch.

A method for fabricating a textile sensor is described in WO2015022671A1 and may include selecting a combination of variables from the group consisting of yarn variables, seam variables, and conductive yarn knitting variables in the textile sensor, wherein the combination of variables is selected to provide a controlled amount of contact resistance in textile sensor. The method and the textile may comprise a capacitive textile sensor having at least two integrally knitted capacitor plate elements and having a configuration adapted to the sensing activity. The resistance in the textile sensor can be automatically calibrated to a stable baseline level after the textile sensor is applied to the body.

A sensor garment that includes a harness is described in patent US10154694B2 In one illustrated embodiment of such a garment and sensor installation includes a textile part, a device retention element connected to the textile part, and a stretchable belt connected to the textile part. The cable harness (wiring) includes a conductive element arranged between layers of film. The conductive element includes a first termination point on the device retention element, configured to connect to a monitoring device. The conductive element includes a second termination point configured to connect to a sensor or transceiver.

One textile strain sensor is shown in patent CN110411622A. The all-textile strain sensor comprises a flexible fabric substrate, a flexible strain sensor and a knot of textile wire for attaching the flexible strain sensor to the flexible fabric substrate, wherein the flexible strain sensor comprises two bundles of conductive fibers, each bundle of conductive fibers having a loose structure and the loose structures of two bundles of conductive fibers are crossed and stacked to form a cross-junction structure. The advantages of the all-textile strain are that it can be cleaned, does not fall off easily, is resistant to motion disturbances, high resolution, high sensitivity, and is compatible with existing textile technology.

Patent WO2016198969A1 describes a multifunctional textile sensor by creating a flexible textile structure with sensing and light capabilities without losing important characteristics of typical textiles, eg comfort, seamlessness and mechanical flexibility. Three different approaches are described as sensing applications that may or may not work together in the same system: a direct printed self-capacitive sensor, a woven textile sensor, and the integration of capacitive sensors for temperature and humidity directly on textiles. As decorative and advertising lighting applications, two different approaches are used that can work individually or together: an electroluminescent sensor device and the use of a hybrid sensor that includes the use of SMD LEDs and a printed self-capacitive sensor.

Patent WO2011134864A1 relates to a shear sensor consisting of two or more electrodes and an electrically conductive textile, wherein said sensor is adapted to measure a change in resistance in response to shear deformation, wherein said textile is comprised of multi-fiber conductive fibers having a very high resistance (between 102 Ohm.cm and 107 Ohm.cm) and stiffness and is not suitable for installation in clothing. Likewise, the mentioned invention contains a polymer matrix and a conductive filler on standardized and common fabric embroideries, which further degrades it when used in garments.

A sensor for measuring physiological electrical signals, EP3169219A1, which consists of: a textile electrode consisting of a detectable textile part for detecting physiological electrical signals and a peripheral textile part which is immediately next to the detection part. The detection part has an electrically conductive surface intended for contact with the individual's skin and is electrically connected to a device for collecting and processing physiological signals detected by the textile electrode.

Patent US2016238468A1 describes a stitched sensor that includes a number of threads sewn by a sewing machine with a certain type of machine sewing stitch on textiles. The plurality of threads includes a conductive thread, and the seam geometry is configured such that the electrical property of the stitched sensor changes based on the stretching, relaxation, or bending of the textile. Methods for shaping the stitched sensor are also described.

1. Sewing techniques and decorative embroidery techniques have been used by various authors to create force sensors and described in scientific works. The decorative embroidery technique is described by Jung-Sim Roh (Roh, Jung-Sim. Conductive Yarn Embroidered Circuits for System on Textiles. 10.5772/intechopen.76627., 2018, 161-174). Orathai Tangsirinaruenart and George Stylios (Tangsirinaruenart, O.; Stylios, G. A Novel Textile Stitch-Based Strain Sensor for Wearable End Users. Materials, 2019, 12) describe a strain sensor made in the technique of machine sewing stitches. Mary Ruppert-Stroescu and Mahendran Balasu investigate the influence of different types of machine sewing stitches on the electrical properties of conductive threads (Ruppert-Stroescu, M.; Balasubramanian, M. Effects of stitch classes on the electrical properties of conductive threads. Textile Research Journal. 2017. 88 ). It should be noted that the techniques of decorative embroidery and sewing do not provide the desired properties for the production of the textile force and stretch sensor described in point 2, primarily due to low elasticity and electrical sensitivity.

2. All sources cited in this state-of-the-art chapter are not inconsistent with the invention for which a patent is sought.

Revealing the essence of the invention in a way that enables the understanding of the technical problem and its solution and stating the advantages of the invention in relation to the state of the art

The textile diagonally woven force and stretch sensor is made in the form of a diagonally woven textile ribbon (1). It consists of two types of threads with precisely defined characteristics: conventional combed multifilament knitted cotton yarn (2) and knitted electroconductive yarn (3). Conventional combed multifilament knitted cotton yarn (2) consists only of cotton combed yarn (4). The finished electroconductive thread (3) consists of twisted cotton combed yarn (4) and electroconductive threads (5). The above-mentioned knitted yarns are woven using the technique of hand bias weaving without a pronounced special weft system in such a way that both types of yarns form a diagonal textile flat fabric in a cloth weave with a characteristic closed edge (6) on which the alternating threads change the direction of the diagonal, and at the same time have the task of preventing the structure from shedding ribbons. The longitudinal effect of force on the textile diagonally woven force and stretch sensor leads to stretching of the ribbon, which leads to its narrowing and a simultaneous increase in yarn density, as well as the appearance of compression forces that affect the diagonally woven electroconductive threads in such a way as to reduce the contact resistance and increase the total electrical conductivity sensor. The operation of the sensor is possible by installing only one or more electrically conductive threads. The sensor is calibrated in such a way as to measure the dependence of the electrical resistance of the incorporated knitted electroconductive yarn at a certain value of the stretching force acting on the ribbon. By knowing the functional dependence of the stretching of the tape on the acting force, it is possible to measure the stretching, that is, the displacement.

The advantages of textile diagonally woven force and stretch sensors are the ability to measure very small forces at relatively large stretches, so they are suitable for installation in clothes that have high stretch properties, so such a sensor does not affect the change in the characteristics of the clothes. In addition, the sensor is of the textile type, so it is flexible and changes its shape in accordance with the changes in the shape of the clothes when worn, and when in contact with the skin, due to its softness and good tactile sensation, it creates a feeling of comfort. The textile structure of the sensor enables it to be incorporated into clothing using conventional clothing technology machines and devices, for example by sewing with a sewing machine.

Short description of the pictures

Fig. 1 shows the surface structure of a textile diagonally woven force and stretch sensor in the form of a textile ribbon (1) with visible diagonally woven electroconductive threads (3) and closed edges of the ribbon (6). The right part of the drawing shows cross-sections of conventional combed multifilament retted cotton yarn (2) and retted electroconductive threads (3) made of twisted cotton combed yarn (4) and electroconductive threads (5).

Legend:

(1) The textile diagonally woven force and stretch sensor is made in the form of a diagonally woven textile ribbon

(2) Conventional combed multifilament knitted cotton yarn

(3) Finished electroconductive thread

(4) Cotton combed yarn

(5) Conductive thread

(6) A closed edge where the threads change the direction of the diagonal

A detailed description of at least one of the ways of carrying out the invention

The textile bias woven force and stretch sensor is made using the manual bias weaving technique, using 12 warp threads. Of the 12 threads used, 9 threads are arranged in a row (120 twists per long meter in the Z direction) made of four threads of undyed combed cotton yarn (220 twists per long meter in the S direction, fineness 42 tex x 4S), and the remaining 3 threads in a row, they are made of two strands of combed cotton yarn (220 twists per meter, fineness 42 tex x 2S) and one double-strand netted strand of electroconductive filament yarn Polyamide 6.6. (117 dtex x 17 x 2Z) with coating of 99% silver (electrical resistance < 300 Ω/m).

Each of the 12 threads, 3m long, is wound on separate coils and inserted into the grooves (of different depths) of the open comb to create the gap necessary for weaving. The ends of the threads are tied together with a strong hook to create thread tension during weaving. At the beginning of weaving, in order to achieve the arrangement of threads, a thread cross was made between two sticks. Oblique weaving is carried out by inserting the first thread from the right side at an angle of about 450 into the created gap of lightly tensioned threads (every second thread is in the upper and lower positions), then laying it in the first free groove on the left side (next to the twelfth thread). The gap is changed (the threads from the upper position are placed in the lower one, and the threads from the lower position are placed in the upper one) and the next first thread is inserted from the right side, laid in the gap next to the thread entered in the previous gap. The process is repeated (continually inserting threads from the right side to the left after each change of gap) achieving the desired density of oblique weaving in the canvas weave (in this case it is 12 threads per 0.8 cm width and 10 diagonally inserted threads per 1 cm) to the required length .

The final result can be achieved by carrying out the entire procedure from left to right.

Claims (2)

1. A textile diagonally woven force and stretch sensor, suitable for installation in clothing, which is made in the form of a diagonally woven textile ribbon consisting of two types of threads of precisely defined characteristics, i.e. of conventional combed multifilament retted cotton yarn and retted electroconductive thread indicated by the fact that the conventional combed multifilament knitted cotton yarn consists only of cotton combed yarn, and the finished electroconductive thread consists of twisted cotton combed yarn and electroconductive threads, with the fact that the knitted yarns are woven using the manual bias weaving technique without a pronounced special weft system in such a way that both types of yarn form a diagonal textile flat structure so that the longitudinal force on the sensor causes the ribbon to stretch, which results in its narrowing and simultaneous increase in yarn density, as well as the appearance of compression forces that affect the diagonally woven electroconductive threads in such a way as to reduce the contact resistance and increase the total electrical sensor conductivity in according to the magnitude of the force. 2. Textile diagonally woven force and stretch sensor according to claim 1, characterized by the fact that it is made in a cloth weave with a characteristic closed edge where the alternating threads change the direction of the diagonal, and at the same time have the task of preventing the tape structure from shedding.